Electrodeposition of copper



Patented Dec. 7 l I 5 52,455,554 5 5 5 annc'monaroslcrion om' camma lienryiBrown, Detroit, Miibh lsmr a m l 5 5 .Udylite Corporation, Detroityilmch a corpora- Ition .of llelaware 5 5 5 'NoDmwing. Application 5, 19%,

.Serial No. 589,112

t Claims. (01. 1204-52.)

5 I I}his -in ention relates to the electrodeposition It .is best-to operate the baths cold (toe-soup of copper tromawmidbath. 5 i roratmoomitemperatures orbelow approximately 5;5;; Ehoiohjectiofithis5 invention is to decrease the J1DQ5,-F. Higher temperatures decrease therate gra ings eiand increase the lustre of the copper oi -brighteningandthebrightplating-range5(the deposit withoutmalteriallyimpairingtheductillt 5 lowercurrentdensityareas are5dul-l)5.5 Too high of plate 5 or5-\decreasing ,the current density rconcentrationsiof acid-do likewise. trange af thecopper plating-nbath. For the highest rate ofbrighteningand the l havedound 1that this5 5object canibe accomwidest bright plating, range, besides a low tem- ,pil" V 4 db?! .tbe-cadditionnf ,small 5-concentrations perature, the use 50f vigorous 5 agitation of, the

5Qf5 la etyl caanamide 5 5 5 i solutiontortcathodeagitationis necessary 55The i 5 55 55 5 use of such agitation besides enhancingwthebril liance emakes the-copper ion concentration even venom-Nam less critical and also makes possible thense of high cathode current densities (100- amp/ft? to standard acid 5 oopper5-plating baths. 5 and (higher) :at which brilliant ,plate is -5obtained Th s compound used in small concentrations k ssimeIthe,use of5 higher 5an0de sung t aw (made up of currenttdenslties. 5 The highest rate of brighten- Simply copper sulfate and sulfuric Wm dng isnbtained :atthe big-her 5 currentqclensities.

cause denv i m very brilliant A preferred 5-5bath -ifro m the standpoint 550f It will also decrease the grain size and increase no emndmyds;

the lustre of the copper plate obtained from the 555 5 also .5H.o 5-5- 5 515.o 200 with the -use-of'0.10.7 g./l. of acetyl -cyanai inidwbrilliant ductile copper plate can be obay; wanamme 4 tained fromithelsnnpleacid5.copper sulfate bath. v 5 The compositionof thebath may vary over wide T m 450475 Vigorous mmfl 5- \rate t the -01 cathode. Cathode if 119-190 mg and Torthe widest bright plating range, it

is best not to use concentrations of sulfuric acid e addition ammoniumsulmte 5 of much over 80 5/ The standard acid c pper of widens Plate plating baths of t compositions given by: range toward the lower current densities, though 5 it does decrease somewhat the rate of brighten- Grams Per liter ing at the very highest current densities. 01180451120 150 t 250 The addition of small amounts (0.005 to 0.1

H2504 10 to g./l.) of gelatin or partially hydrolyzed gelatin give very good results, though less copper sul- Partially hydro yzed g t p pt nes 1mfate n l d may b d proves the brightness further but decreases the The following acidic copper plating baths can ductility- 5 v be used with improved results in smoothness and Acetyl cyan mi e s a efi impmvement brightness by the addition of about 0.1 to 0.7g./l. 0V6! cyanamide or dlcyandiamide, in that the of acetyl cyanamide: 40 bright plate range is wider, and there is less Exam 1 A tendency for ribbing effects at the higher conp e 5 centrations of brightener. Also for a given de- CuSO 5H2O Grams per gree of brightness the plates are more ductile. H2804 10-25 45 I claim' 1. A bath for electrodepositing bright copper Example B comprising an aqueous acid copper solution com- Grams per liter prising essentially a material selected from the CUSO4.5H2O 150 group of materials consisting of copper fluoborate, (NED-2804 10-50 a mixture of copper sulfate and sulfuric acid, a HaSOr 10 20 mixture of copper sulfate, ammonium sulfate and Example c sulfuric acid, a mixture of copper fluoborate and Grams per liter hydrofluoboric acid, and a mixture of copper CMBFOZ copper fluobomte) 100450 fluoborate, ammonium fluoborate and hydro- Free Fr fluoboric acid, said aqueous acid copper solution 5 also having dissolved therein acetyl cyanamide in Eimmple D a concentration ranging from about .1 to .7 gram Grams p liter per liter, said bath having a temperature falling CuBF'4 5 within a range of from about 50 F. to about 100 NHI4BF'4 1 -50 F, and containing a greater molar concentration mam 5 -2 60 of copper salt than or acid.

tion falling within a range of from about 150, grams per liter to about 200 grams per liter and" sulfuric acid in a concentration; falling withina;

range of from about grams per liter to about grams per liter and having dissolved therein per comprising the stepot elg ctrodepositing copper. from an aqueous j acid cobbe'rjq solutlon comprising essentially copper "sulfate in 'a'concentrati on falling within a range of from about 150 grams per liter to about 200 grams per liter and ,sulfurimacidima concentration falling within a acetyl cyanamide in an amount falling within a range of from about .1 gram per liter to about .7

gram per liter, said bath having a temperature:

about 100 F.

3. A bath for electrodepositing bright 'co pper' comprising an aqueous acid copper solution comprising essentially copper fiuoborate'in a concentration falling within a range of from' ab'out 100 grams per liter to about 150 grams per liter and hydrofluoboric acid in a concentration falling within a range of from about 5 grams 'per liter to about 25 grams per liter and having dissolved 'thereinacetyl cyanamidein an amount falling within a range of from about .1 gram per liter to about/.7 gram per liter, said bath having a temperature falling within a'range of from about 50 F.toabout 100 F. i 4. Themethod of electrodepositing bright copper comprising the step of electrodepositing copperfrom an aqueous acid copper solution having dissolved therein a material selected from the group'of materials consisting of copper fiuoborate, a mixture or copper sulfate and sulfuric acid, a mixture of copper sulfate, ammonium sulfate and sulfuric acid; a mixture of copper fiuoborate and hydrofluoboric acid, and a mixture of copper fluoborate, ammonium fluoborate and. hydrofluoboric acid, said aqueous-acid copper solution also having dissolved therein acetyl cyanamide in a concentration ranging from about .1 to .7 gram per liter, said bath having atemperature falling within a range of from about 50F. to about 100 F. and containing a greater molar concentration of copper salt than of acid..v

5. The method of electrodepositin bright coprange of from about 10 grams per liter to about 25 grams perfliter' and. having dissolved therein acetyl cyanamide in an amount falling within a range of from about .1 gram per liter to about .7

, :gram .per liter, said bath having a temperature falling within a range of from about fiFxito falling Within a range of from about 50 F. to about F.

' 6. The method of electrodepositing bright copper comprising the step of electrodepositing copper from an aqueous acid copper solution comprising essentially copper fluoborate in a concen- 'tration falling within'a range of from about 100 grams per liter to'about gramsper liter and hydro'fiuoboric acid in a 1 concentration "falling within arange of from about 5 gramsper liter to about 25 grams perliter and having dissolved therein acetyl cyan'amide in" an amountjfalling within a range of from aboutfll gram per-liter to about .7 gram per liter, said bath having a. temperature falling within a range of from about 50 F. to about 100 F.

" HENRY BROWN.

1 The following references are ,of-record in the .file ofthis patent:

UNITED STATES PATENTS Number, I ,Name .Date

2,164,924 Hull July 4, 1939 2,374,289 Hull Apr. 24,-1945 

